Unified Modelling Language

Transcription

1 Unified Modelling Language Phil Robinson

2 What is the UML? A language that unifies the industry s best engineering practices for modelling software systems Goals Simple and extensible Broad application Implementation independent Process independent

3 The Evolution of the UML Introducing the Three Amigos

4 Mid 70 s - Mid 90 s Competing object oriented methods Booch OMT (Rumbaugh) OOSE (Jacobson) Others

5 1995 Unified Method Booch Rumbaugh

6 1996 Booch and Rumbaugh are joined by Jacobson They become the Three Amigos Unified Method becomes Unified Modelling Language The UML Partners begin working with the Amigos

7 1997 UML 1.0 proposal submitted to the Object Management Group (OMG) UML 1.1 Adopted as an OMG standard

8 UML Since Adoption ? 2001? UML 1.2 (editorial clean up) UML 1.3 (technical revision) UML 1.4 (planned minor revision) International standard (ISO) UML 2.0 (planned major revision)

9 Object Oriented Software

10 Hardware Architecture MEMORY CPU Unchanged since 1950 s Separation of data and logic Strong influence on software development

11 Conventional Software MEMORY char name, address; float balance, amount; CPU... balance = balance + amount;...

12 Object Oriented Software Object Classes reflect the problem domain (rather than the hardware architecture) Information hiding Normalisation of logic Easier to reuse

13 Development is Different Conventional Separate data and function models Decomposition guides modelling Paradigm changes throughout the development lifecycle Danger of logical spaghetti Object Oriented Single object model with many views Abstraction guides modelling Consistent paradigm throughout the development lifecycle Danger of logical ravioli

14 External System Behaviour Externally visible behaviour User s perspective Black box view

15 System Structure Classes Instances Relationships

16 Internal System Behaviour Collaborations Object instances Messages Developer s perspective Glass box view

17 Internal Object Behaviour Behaviour Operations Methods State Attributes

18 UML Diagrams Class/Object Diagrams (System structure) Use Case Diagrams (External system behaviour) Sequence Diagrams (Internal system behaviour) Statechart Diagrams (Internal object behaviour)

19 Class/Object Diagrams System Structure

20 Classes Transaction itemnumber transactiontype date amount SavingsAccount accountno name /balance rate openaccount(accountno,name) deposit(amount,date) withdraw(amount,date) balance() close()

21 Objects Jones:SavingsAccount Abbot:SavingsAccount Smith:SavingsAccount :SavingsAccount

22 Relationships Transaction itemnumber transactiontype date amount new(type,amount,date) returnamount() * 1 Account account_no name /balance open_account(accountno,name) deposit(amount,date) withdraw(amount,date) updatebalance(amount) interestcalc() returnbalance() closeaccount() SavingsAccount rate LoanAccount rate interestcalc() interestcalc() HousingLoan CreditCard openaccount(name) withdraw(amount,date) interestcalc()

23 Use Case Diagrams External System Behaviour

24 Use Case Components Actors Use case Basic scenario Alternate scenarios Extends Includes

25 Use Case Diagram Withdraw extension points account overdrawn <<extends>> Account Overdrawn Deposit Teller <<includes>> Balance Enquiry <<includes>> Update Balance Open Account Customer Service Representative Close Account <<includes>> Calculate Interest Mont End <<temporal>>

26 Sequence Diagrams Internal System Behaviour

27 Sequence Components Objects Life lines Activations Messages

28 Sequence Diagram :Loan Account bal:=withdraw(amount, date) tr:=new(type, amount, date) tr:transaction update balance(-amount)

29 Statechart Diagrams Internal Object Behaviour

30 Statechart Components States Transitions Events

31 Statechart Diagram Accounts with a zero balance are considered to be in credit Deposit Deposit [amount+balance<0] Open Account (1) Account in Credit Withdraw [amount>balance] Deposit [amount+balance>=0] (2) Account Overdrawn Bad Debt (3) Close Account [balance=0] Withdraw [amount<=balance]

32 But there s more...

33 Modelling Elements Collaboration diagrams Activity diagrams Interfaces Packages Realise relationship Dependency relationship Object Constraint Language (OCL) Extension mechanisms

34 Implementation Deployment Nodes Connections Components Repository based development Round trip development tools

35 Process UML describes software development artefacts The Unified Software Development Process Use case driven Architecture centric Iterative and incremental UML can be used with other processes

36 Unified Modelling Language Phil Robinson